Disorder Scattering Induced Large Room Temperature Nonlinear Anomalous Hall Effect in a Semiconductor CdGeAs₂

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Electronics

Background:

• The nonlinear Hall effect (NLHE) is a significant phenomenon in condensed matter physics with potential applications.
• Previous research on NLHE primarily focused on 2D materials, facing limitations in operating temperature and responsivity (typically < 10^-4 m/V).
• Achieving high responsivity at room temperature in 3D systems, especially for scattering-induced NLHE, has been a persistent challenge.

Purpose of the Study:

• To discover and characterize disorder scattering-induced NLHE in 3D bulk single crystals.
• To investigate the potential of NLHE in 3D materials for practical applications, particularly at room temperature.
• To explore the frequency mixing capabilities of NLHE in 3D systems.

Main Methods:

• Experimental synthesis and characterization of chalcopyrite-type CdGeAs₂ bulk single crystals.
• Measurement of nonlinear Hall effect properties, including responsivity and anomalous Hall angle.
• Band structure analysis using Angle-Resolved Photoemission Spectroscopy (ARPES) and Density Functional Theory (DFT) calculations.
• Symmetry analysis and nonlinear Hall conductivity scaling to identify the dominant NLHE mechanism.

Main Results:

• Discovery of disorder scattering-induced NLHE in CdGeAs₂ bulk single crystals with a record room-temperature responsivity up to 10^-3 m/V.
• Demonstration of ac-driven second harmonic and rectification Hall responses, along with a large anomalous Hall angle.
• Identification of disorder scattering as the primary mechanism driving NLHE in CdGeAs₂ through comprehensive analysis.
• Exhibition of broadband electronic frequency mixing capabilities in the MHz range at room temperature.

Conclusions:

• Disorder scattering is a viable mechanism for achieving significant NLHE in 3D materials at room temperature.
• CdGeAs₂ exhibits promising properties for next-generation electronic devices.
• This work paves the way for integrating scattering-induced NLHE in 3D materials into high-frequency mixing technologies.